Self-Assembled Chitosan/Cu-β-Cyclodextrin Composites for Selective Electrochemical Identification of Phenylalanine Enantiomers

The enantioselective recognition of biomolecules such as amino acids has significant value in medicine, life sciences, agriculture, and other fields. In this study, a novel electrochemical chiral sensor, CS@Cu-β-CD/GCE, was successfully prepared by self-assembling Cu 2+ modified β-cyclodextrin (β-CD) with chitosan (CS) and coating it onto a glassy carbon electrode (GCE). This method effectively addresses the agglomeration issues associated with CS while significantly enhancing the conductive properties of the material and increasing the number of chiral recognition sites. Experimental testing and structural analysis revealed that differentiated hydrogen bonding provides the driving force for molecular binding, while the confinement of the Cu-β-CD cavity and steric hindrance enable structure selection. At optimized testing conditions (30 s incubation, 25°C, pH = 6.0, 5.0 mM), it exhibited the peak current ratio (I D /I L ) of up to 2.25 for phenylalanine (Phe) isomers, outperforming most previously reported electrochemical sensors. Meanwhile, the CS@Cu-β-CD/GCE exhibits excellent stability (98.6% signal retention after 16 days of storage at 5°C), high enantiomeric selectivity for Phe, and good resistance to interference, can be developed for distinguishing racemic phenylalanine. This strategy provides a simple and efficient approach for electrochemical chiral identification of Phe enantiomers and holds wide-ranging application prospects in chiral sensing and drug analysis.